Bridge for stringed musical instruments



April 969 T.- M. MCCARTY 3,440,921

BRIDGE FOR STRINGED MUSICAL INSTRUMENTS Filed Oct. 25, 1967 INVENTOR.Mame! M. 44004577 ,47 TUBA [1 6' United States Patent BRIDGE FORSTRINGED MUSICAL INSTRUMENTS Theodore M. McCarty, Kalamazoo, Mich.,assignor to Bigsby Accessories, Inc., Kalamazoo, Mich, a corporation ofMichigan Filed Get. 25, 1967, Ser. No. 678,119 Int. Cl. Gltld 3/04 U.S.Cl. 84--307 Claims ABSTRACT OF THE DISCLOSURE An adjustable bridgeassembly for a stringed musical instrument whereby the saddle memberthereof can be raised or lowered relative to the sounding board as desired. The saddle member is seated within a slot provided in a soundingbar positioned within the hollow body of the musical instrument. Thesaddle member extends outwardly through a further slot provided in thesounding board and projects above the surface thereof for supportingthestrings. The sounding bar is connected to the sounding board byadjustable fastening means, such as screws, for permitting the soundingbar and saddle mem- 'ber thereon to be raised or lowered.

Field of the invention This invention relates to a bridge for a stringedmusical instrument and, in particular relates to a bridge assembly whichpermits the position of the saddle portion thereof to be easily adjustedrelative to the sounding board of the instrument.

Description of the prior art In stringed musical instruments, theposition or height of the bridge relative to the surface of the soundingboard of the instrument is a critical limitation. For example, if thebridge is positioned too high with respect to the sounding board, thenthe strings of the instrument are excessively spaced from the neckportion of the instrument and, accordingly, the user of the instrumentfinds it diflicult to play the instrument due to the diificulty intightly gripping the strings betwen the fingers and the neck portion. Onthe other hand, if the bridge is too low, then the strings contact orvibrate against the neck of the instrument when played, thus producing aharsh and unpleasant noise instead of, or in addition to, a musicaltone. Accordingly, it is desirable to position the bridge as low aspossible relative to the sounding board so as to facilitate playing ofthe instrument, while at the same time maintaining sufiicient spacebetween the strings and the instrument to insure that same will notvibrate against the instrument.

In most stringed instruments, the bridge includes a saddle member whichis normally fixed within a blind groove formed in the surface of thesounding board or in the surface of a base member mounted on thesounding board. However, this type of mounting arrangement has provedundesirable since, when the weather is hot and humid, the sounding boardswells and :thus causes a greater separation or distance between thestrings and the instrument, thereby making playing of the instrumentmore difiicult. Thus, it is often necessary to sand down the surface ofthe saddle to maintain the proper spacing between the strings and theinstrument. However, when the weather then becomes cold and dry, thesounding board shrinks and causes the strings to be positioned too closeto the instrument whereby same vibrate against the instrument duringplaying. Since the saddle has been previously sanded down, it is nownecessary to remove the old saddle and replace same with a new saddle soas to obtain the desired spaced between the strings and the instrument.While this procedure has been effective, such sanding and replacing ofthe saddle is not only costly, but unnecessarily time consuming.

Accordingly, it has been suggested that the saddle be adjustably mountedon the stringed instrument so as to permit adjustment of the positionthereof according to the climatic seasons and environmental conditions.While several different adjustable bridge assemblies have been proposed,none of these devices have proven highly successful since they haveeither been fairly complex and expensive to manufacture, or haveadversely affected the tonal quality of the instrument.

Accordingly, it is an object of this invention to provide:

(1) An adjustable bridge assembly for a stringed musical instrument.

(2) An adjustable bridge assembly, as aforesaid, which permits theposition of the bridge to be quickly and easily adjusted relative to thesound board of the instrument.

(3) An adjustable bridge assembly, as aforesaid, which does not destroyor adversely affect the tonal quality of the instrument.

(4) An adjustable bridge assembly, as aforesaid, which utilizes ametallic sounding bar positioned within the body of the instrument.

(5) An adjustable bridge assembly, as aforesaid, which is highlyeffective to support and anchor the strings of the instrument and at thesame time is compact and attractive.

(6) An adjustable bridge assembly, as aforesaid, which is economical tomanufacture and simple to mount on a stringed instrument.

Other objects and purposes of this invention will be apparent to personsacquainted with apparatus of this general type upon reading thefollowing specification and inspecting the accompanying drawings.

Brief description of the drawings FIGURE 1 is a plan view of a guitarembodying the present invention, the neck of the guitar being partiallybroken away.

FIGURE 2 is an enlarged fragmentary sectional view, partially brokenaway, as taken on the line Il-II of FIGURE 1.

FIGURE 3 is an enlarged fragmentary sectional view as taken on the lineIlIIlI of FIGURE 1.

FIGURE 4 is en enlarged fragmentary view, partially in cross section,illustrating a modification of the present invention.

FIGURE 5 is a fragmentary view from the underside of the sound board ofthe instrument.

Certain terminology will be used in the following description forconvenience in reference only and will not be limiting. The wordsupwardly, downwardly," rightwardly and leftwardly will design-atedirections in the drawings to which reference is made. The wordsinwardly and outwardly will refer to directions toward and away from,respectively, the geometric center of the de-- vice and designated partsthereof. Said terminology will include the words above specificallymentioned, derivatives thereof and words of similar import.

Summary of the invention In general, the objects and purposes of theinvention are met by providing an adjustable bridge assembly having abase member which is secured to the surface of the sounding board of amusical instrument. The base member and the sounding board are providedwith a slot which extends into the interior of the hollow body formingthe musical instrument. A saddle member is slideably positioned withinthe slot and has one end thereof extending upwardly above the basemember so as to contact and support the strings of the instrumentthereon. The other end of the saddle member is received within a grooveformed in a sounding bar positioned in the interior of the musicalinstrument. The opposite ends of the sounding bar are connected to thebase member by means of a pair of adjustable fastening elements, such asscrews, whereby rotation of one or both of the screws permits thesounding bar and the saddle carried thereon to be raised or loweredrelative to the sounding board for adjusting the height of the stringsrelative to the body of the instrument.

Detailed description In the accompanying drawings, FIGURE 1 illustratesa conventional stringed instrument 11, such as a guitar, whichinstrument is of conventional construction and comprises a hollow body12 having a sounding board 13 thereon. Reinforcing ribs 8 and 9 and abridge supporting block 10 are provided in a conventional manner to theunderside of the sounding board 13. A neck 16 is connected to the body12, the neck having conventional transverse frets extending thereacross.The neck is provided with conventional tuning pins 71 on the end thereofto which is connected one end of the strings 18, the other end of thestrings being anchored or connected to the adjustable bridge assembly19.

The adjustable bridge assembly 119 comprises a base member 21 formed ofwood or other suitable material and preferably secured to the soundingboard 13 by means of glue or other adhesive. The front edge 22 of thebase member is in this embodiment substantially transverse to thelongitudinal axes of the strings. The base member is provided'with alongitudinally extending slot 23 therein, which slot is slightlyinclined relative to the front edge 22 of the base member to vary thelength of the different strings in relation to their diameter in amanner and for purposes which are already well known. A similar slot 26is formed in the sounding board 13 and support block 10 such that, whenthe base member is secured to the sounding board, the slots 23 and 26are positioned one above the other so as to form a substantiallycontinuous slot extending into the interior of the body 12 asillustrated in FIGURE 3. A saddle member 27 is slideably received withinthe slots 23 and 26 and positioned between the ribs 8 and 9 with theupper edge 28 of the saddle member extending beyond the upper surface ofthe base member 21. The lower edge 29 of the saddle member projectsbelow the ribs 8 and 9 and is received within a groove 31 formed in asounding bar 32 located within the interior of the body 12 and below theribs 8 and "9. The bridge member 27 is desirably fixed to the soundingbar 32 by means of a screw member 33.

The sounding bar 32 is suspended within the interior of the body 12 bymeans of a pair of adjustable fastening elements, such as screws 36 asillustrated in FIGURE 2. In this embodiment the ribs 8 and 9 extendbetween the saddle and respective screws 36. Each of the screws 36 is,in this embodiment, provided with a conventional slotted head 37 at theupper end thereof which is positioned adjacent the upper surface of thebase member 21. The lower ends of the screws 36 are each threadedlyengaged with the sounding bar 32 adjacent opposite ends thereof. Thebase member 21 and the sounding board 13 are each provided withcoaxially aligned openings therein in which is received a cylindricalbushing 38, which bushing has a flange or shoulder 39 at the upper endthereof in bearing engagement with the upper surface of the base member21. The bushings 38 thus permit the screw members 36 to slideably moverelative to the base plate 21 and the sounding board 13.

The base member 21 is further provided with a plurality of holes 41therein spaced longitudinally of the bridge member. The strings 18 passover the upper edge 28 of the saddle member 27 (FIGURE 3) with theextreme end of each string being disposed within one of the holes 41 andsecured therein by means of a wedging pin 42 or similar device. Ifdesired, the upper edge 28 of the saddle can be provided with stringnotches therein for maintaining the desired transverse spacing betweensaid strings.

The contact of the strings on the upper edge 28 of the saddle, combinedwith the tension which exists within the strings, causes a downward orpushing force to be exerted on the saddle. The force exerted on thesaddle member 27 is transmitted to the sounding bar 32 which in turnimposes a tensile force on the screws 36 whereby said screws are pulleddownwardly causing the heads 37 thereof to be maintained in snug bearingengagement with the flanges 39 formed on the bushings 38. Thus, thetension which exists in the strings maintains the adjustable bridgeassembly in the desired adjusted position and thus the screw members 36can be freely slideably received within the bushings 38.

The sounding bar 32 is preferably constructed of aluminum so as topermit a clear and undistorted transmission of sound therethrough.However, other suitable metallic materials could be utilized, the onlyrequirement being that the material be hard enough, as is already wellknown in the art, to transmit sound therethrough while being soft enoughso as to not generate a ringing sound. The saddle member 27 ispreferably constructed of any reasonably hard and stiff plastic whichcan be easily and inexpensively manufactured.

Operation Although the operation of the device embodying the inventionhas been indicated somewhat above, said operation will be described indetail hereinbelow for a better understanding of the invention,

When it is desired to adjust the height of the bridge member 19 withrespect to the base member 21, said adjustment can be easilyaccomplished merely by rotating the threaded screw members 36 by meansof a conventional tool, such as a screwdriver or coin. Rotation of bothof the screw members 36 will cause the sounding bar 32 to be eitherraised or lowered relative to the sounding board 13 depending upon thedirection of screw rotation. This in turn will cause the saddle member27 to be correspondingly raised or lowered relative to the upper surfaceof the base member 21, thereby adjusting the clearance which existsbetween the strings 18 and the body of the instrument. If it is desiredto adjust the height of only one end of the saddle member, same can beaccomplished merely by rotating the screw positioned adjacent that endso as to cause a raising or lowering of the saddle member. Since thedifferential adjustment in the height of one end of the saddle memberrelative to the other end is of a very small magnitude, no binding ofthe saddle member will occur due to the fact that suflicient clearanceis provided between the screw members 36 and the surrounding sleevebearings 38 for accommodating such slight angularities.

FIGURE 4 illustrates a modification of the present invention wherein thethreaded screw members 36 having conventional slotted heads 37 thereonare replaced by threaded members 37A having knurled wheels 46 fixedlysecured adjacent the upper ends thereof. The screw members 37A coactwith the overall assembly in substantially the same manner as the screwmembers 37, that is, the lower end of the screw members 37A threadedlyengaged the sounding bar 32 adjacent opposite ends thereof while thelower surface of the knurled wheels 46 are held in bearing engagementwith the flange 39 of the bearing sleeve 38. However, in somesituations, the threaded screw member 37A having the knurled wheels 46thereon are desirable since same permit the saddle height to be adjustedmerely by gripping the knurled wheels between the thumb and forefingerand rotating the screw members in the desired direction until thedesired height is achieved. Thus, this modification does not require theuse of a special tool, such as a screw driver, for adjusting the heightof the saddle member.

A still further modification of the invention resides in the position ofthe base member 21 with respect to the body 12 of the instrument. Asillustrated in FIGURE 1, the base member is provided with a portion 47which extends outwardly in a direction away from the neck 16 of theinstrument. However, if desired, the base member 21 could be rotated 180degrees within the plane of the sounding board 13 whereby the extendingportion 47 would then extend in a direction toward the neck 16. Thisstructure will in some cases be desirable since the large extendingportion 47 provides an increased support tending to prevent twisting ortipping of the base member 21 due to the moment imposed thereon by thetension within the strings.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. An adjustable bridge assembly for a stringed musical instrumenthaving a sounding board, comprising:

a base member having a first surface thereon adapted to be mounted onthe sounding board of such instrument, said base member having a slotextending through said member and extending through said sounding board;

a sounding bar spaced from said base member and positioned on the sidethereof facing said surface;

adjustable fastening means extending through said surface andinterconnecting said sounding bar and said base member for permittingadjustment in the spacing therebetween; and

a saddle member slideably received within and extending through saidslot and bearing against said sounding bar.

2. An adjustable bridge assembly as defined in claim 1, wherein:

said fastening means includes a threaded member having one end thereofthreadedly received within one of said sounding bar and said basemember, the other end of said threaded member being provided with anenlarged head thereon with said head being in bearing engagement withthe other of said sounding bar and said base member.

3. An adjustable bridge assembly as defined in claim 1, wherein:

said base member is provided with a hole substantially adjacent each endof said slot;

said fastening means comprising a pair of threaded members with one endof each of said threaded members being slideably received within one ofsaid holes, the other end of each of said threaded members beingthreadedly engaged with said sounding bar adjacent opposite endsthereof.

4. An adjustable bridge assembly as defined in claim 3,

wherein:

said threaded members are provided with enlarged head portions on thesaid one end thereof, said head portions being positioned on the side ofsaid base member opposite said sounding bar.

5. An adjustable bridge assembly as defined in claim 1, wherein:

said sounding bar is provided with a longitudinally extending groovetherein, one edge of said saddle memher being received within saidgroove.

6. An adjustable bridge assembly as defined in claim 1, wherein:

said sounding bar is constructed of aluminum.

7. An adjustable bridge assembly as defined in claim 1, wherein:

said base member is provided with a pair of openings extendingtherethrough substantially adjacent the 0pposite ends of said slot;

said fastening means comprising a pair of threaded members with one endof each of said members being slideably received within said openings,the other end of each of said threaded members being threadedly engagedwith said sounding bar adjacent 0pposite ends thereof;

said threaded members being additionally provided with enlarged headportions adjacent said one end thereof, said head portions beingpositioned adjacent said base member on the side thereof opposite saidsounding bar;

said sounding bar having a groove formed in one surface thereof withsaid groove being substantially parallel to the slot formed in said basemember;

said saddle member extending into and through said slot and having oneedge thereof received within the groove formed in said sounding bar,whereby the opposite edge thereof is positioned adjacent the oppositeside of said base member.

8. An adjustable bridge assembly as defined in claim 7, wherein:

said enlarged head portion is provided with gripping means thereon forpermitting rotation of said threaded member.

9. An adjustable bridge assembly as defined in claim 7, wherein:

lock means are provided for interconnecting said saddle member to saidsounding bar.

10. An adjustable bridge assembly for a stringed musical instrumenthaving a sounding board with reinforcing means on the inner sidethereof, comprising:

a base member having a first surface thereon adapted to be mounted onthe sounding board of such instrument, said base member having a slotextending through said member, and a further slot in register with saidlast-named slot extending through said sounding board;

a sounding bar spaced from said one surface and positioned on theopposite side of both said sounding board and said reinforcing meansfrom said base member;

adjustable fastening means extending through said surface andinterconnecting said sounding bar and said base member for permittingadjustment is the spacing therebetween; and

a saddle member slideably received within and extending through saidslot and engaging said sounding bar.

References Cited UNITED STATES PATENTS 2,025,875 12/1935 Loar 8412,905,042 9/1959 Hoyer 84-307 RICHARD B. WILKINSON, Primary Examiner.

GARY M. POLUMBUS, Assistant Examiner.

